The Remote Sensing Device
A system that remotely measures the actual emissions from each vehicle
Opus Remote Sensing Device (RSD) remotely measures exhaust emissions from motor vehicles as they drive by the sensing site on streets and highways. The emissions are measured spectroscopically, by casting a narrow infrared (IR) and ultraviolet (UV) beam of light across the road and through the trailing exhaust of passing motor vehicles. A mirror then reflects the IR/UV light back to a series of detectors that measure the amount of transmitted light at characteristic wavelengths absorbed by the pollutants of interest.
The RSD can measure the emissions emitted by the vehicles circulating under real-driving conditions. Since it takes only a second to capture a measurement, these devices can capture large quantities of vehicle emissions data in a short period of time. Also, since it is a non-intrusive technique, the RSD monitors the vehicles without interfering with the traffic flow.
In brief, the system measures the spectroscopic absorbance in IR and UV light of:
- Hydrocarbons (HC)
- Carbon monoxide (CO)
- Carbon dioxide (CO2)
- Nitrogen monoxide and dioxide (NO and NO2 separately, combined as NOx)
- Ammonia (NH3)
- Particulate matter as a proxy from opaccity (PM)
By taking the ratios of the various pollutants to CO2 and applying stoichiometric rules and other conversion factors, the emission values can be epressed in meaningful units (i.e. g/kg fuel burned), which can then be converted to travelled distance emissions (g/km) with appropriate assumptions.
Exhaust emissions are measured instantly, accurately and non-intrusively
What does the RSD measure?
The RSD measures the concentrations of Carbon Monoxide (CO), Hydrocarbons (HC), Oxides and Dioxides of Nitrogen (NO and NO2), Particulate Matter (PM) and Amonnia (NH3). The system shines beams of ultraviolet and infrared light across the road. The amount of specific wavelengths of light absorbed by the pollutant in the vehicle's exhaust and evaporative emissions is recorded and those readings enable us to determine the concentrations of pollutants present in the exhaust plume of the vehicle. The sensors detect emissions from tailpipe exhausts, as well as evaporative emissions caused by leaks from fuel lines, pumps, tanks and other components. The device also captures the licence plate of the vehicle and measures the vehicle's speed and acceleration at the time of the emissions' measurement. All of this completes a "record". The RSD detects and measures each vehicle as the vehicle drives by. The process of measuring emissions remotely begins when the vehicle breaks the invisible beam crossing the road. Each vehicle record consists of 100 measurements of the exhaust plume in 0,5 seconds. Exhaust emissions, speed, acceleration, ambient conditions, the license plate text, the time stamp and other parameters are all recorded in less than a second. All that information relates to a unique record. That record is transferred by 4G/5G in real-time to our Remote Sensing Data Platform.
Portable setup
The most typical configuration of our technology is a portable setup for flexible monitoring and easy deployment. The RSD can be quickly deployed (20 minutes including calibration), left temporarily unattended and frequently moved to fresh sites. The RSD is fully battery powered, connected to the internet and do not require any modification to the road.
The battery pack provides 20 hours of autonomy, and they can be easily swapped. The video camera can be deployed in a hidden barrel, in disguised roadside elements, attached to nearby infrastructure or simply deployed on the roadside with a tripod.
The portable deployment offers maximum flexibility.
Fixed setup
The RSD6000 can also be installed on a fixed site for 24/7 monitoring. The RSD modules are housed inside two main IP65 cabinets, deployed at both sides of the road, and anchored to the ground.
The main cabinet is connected to an external power source, for continuous power supply . The RSD6000 can include a rain sensor which activates the closing of the cabinet if rain is detected. Door is opened again automatically after rain stops.
After installation of the two cabinets, and by providing one of the cabins with electricity, the RSD6000 can be placed inside to measure continuously and uninterruptedly. These cabinets include a full temperature conditioning system.
Key features
Accurate measurement of all critical and regulated pollutants
The RSD6000 measures CO, NO, NO2, HC and NH3 to CO2. Additionally, it provides an accurate measurement of particle emissions equivalent to PM2.5. It is the only technology of its type to provide all this information.
Internal calibration cells
The RSD6000 includes a system for automatic and autonomous auditing. The system incorporates internal sealed cells with known concentrations of multiple gases to regularly verify the system's accuracy. This applies both for portable and fixed systems, enabling 24/7 monitoring with fully unattended operation, while maintaining a method of instrument verification for metrological and legal purposes.
Multi-purpose smart camera
The RSD6000 can include a new advanced camera that provides many solutions altogether: License plate reading, automatic real-time vehicle type recognition, driving lane identification and measurement of speed and acceleration. Thank to this last capability, the new RSD 6000 does not require the legacy speed-bar.
Dual-lane
The RSD6000 can simultaneously measure emissions from vehicles traveling in two lanes without the need to place anything on the asphalt or above the lanes. The system identifies events where vehicles pass in parallel to mark these events as invalid.
A complete, advanced and mature technology
ISO-17025
Opus RSE is the only entity in the world accredited to measure real-driving emissions remotely. Systems are calibrated under ISO methodology. We are audited by the Spanish Acreditation Agency every year.
Cost-effective
We provide the cheapest technology to measure real-world traffic emissions. Either for a one-shot study or for long-term programs, the RSD has proven to be very atractive for our clients.
Easy to use
Worldwide partners and clients use the RSDs on their own after a few days training. The RSD is easy to calibrate in a few minutes and it can be monitored remotely by a technician (PC, smartphone, etc.).
Accurate
Opus RSD correlates with other similar technologies, such as PEMS, by up to 90%.
It is has been a proven and validated system for decades. Even nowadays, independant validations are performed every year.
Flexible
The portable RSD is deployed without any preperation on the site, so it can be deployed on a new site every day. The system can also be inegrated in cabins, gantries or other road infraestructure for fixed deployment.
Integrable
The system is designed to inegrate with all ITS, like ALPR cameras, urban sensors, tollboths, etc. Its small size and simplicity facilitates physical integration. Its connectivity ensures any data integration.
How effective is the RSD?
Our ISO-17025 accreditation gives us a remote measurement accuracy of 15%, similar to other road traffic measurement systems. Our accreditation allows us to ensure the accuracy, relative uncertainty and repeatability of our measurements. In addition, our system has a 90% correlation with PEMS and has been validated by multiple independent international bodies.
